In a blender, combine limeade, tequila, and Grand Marnier. Fill with ice and blend until smooth.
Place the coarse salt in a shall dish or saucer. Wet the rim of 4 glasses with a lime wedge and dip the glass into the salt to coat.
Pour about 1/4 cup of the margarita into each glass. Top with about 1/4 cup of the strawberry puree. Top with more margarita followed by the mango puree. Top with the remaining margarita.
Garnish with a strawberry on the rim of the glass and a slice of mango.